Lacanobia subjuncta
Pest description and crop damage Also known as speckled cutworm moth, the adult is about 1 inch long and has a distinctive color pattern of scales on the wing that range from light brown to black. The appearance of the larva varies with age: young larvae resemble green fruitworms (green with a lateral stripe), while older larvae may be bright green to tan to a light red or brick color. Mature larvae have a herringbone pattern on the dorsal side and may be up to 2 inches long.
Larvae can defoliate shoots. Older larvae also feed on the fruit. Typically, the feeding damage resembles a small scoop removed from the fruit.
Biology and life history The insect overwinters as a pupa in the soil and adults emerge in May and June. Eggs may be deposited in fruit trees or on weed hosts. The first-generation larvae appear in June and July and feed principally on foliage, but may also feed on fruit. Larvae are voracious feeders and can defoliate shoots in a few days. The emergence of second-generation adults begins in late July and they are active through October. Larval feeding from the second generation begins in mid-August and larvae can be found in October.
Scouting and thresholds Examine fruit clusters shortly after fruit set for the small green larvae. They tend to occur in clumps, so thorough monitoring is required.
Management-cultural control
Home orchardists: Adults can be collected in black-light traps. Hand-pick larvae when thinning fruit.
Management-chemical control: HOME USE
Spring and summer
- azadirachtin (neem oil)-Some formulations are OMRI-listed for organic use.
- carbaryl-Highly toxic to bees.
- pyrethrins-Some formulations are OMRI-listed for organic use.
- spinosad-Highly toxic to bees. Some formulations are OMRI-listed for organic use.
- zeta-cypermethrin-Highly toxic to bees.
Management-chemical control: COMMERCIAL USE
Spring and summer
- chlorantraniliprole (Altacor) at 3.0 to 4.5 oz product/A in no less than 100 gal water per application. Do not apply more than 9 oz per acre per growing season. Do not use an adjuvant within 60 days of harvest. REI 4 hr. PHI 5 days. [Group 28] [ovicidal and larvicidal]
- emamectin benzoate (Proclaim 5SG) at 3.2 to 4.8 oz/A in up to 100 gal water per application. Do not exceed 14.4 oz/A per growing season. REI 12 hr (48 hr for workers performing propping, pruning, thinning and tying). PHI 14 days. [Group 6].
- indoxacarb (Avaunt) at 3 to 6 oz/A in up to 100 gal water per application. Make no more than three applications prior to hand-thinning. No hand thinning after the fourth application. Make no more than four applications per growing season. Do not apply more than 24 oz/A per growing season. Apply in spray volume of up to 200 gal/A. REI 12 hr. PHI 14 days. [Group 22]
- novaluron (Rimon) at 20 to 50 fl oz/A in 100 gal water per application. Apply when lacanobia eggs have hatched and larvae are in first to third instar range. Do not use Rimon in alternate row middle application patterns since this method will result in off-timing application and poor performance. Do not apply more than four applications or more than 150 fl oz/A per growing season. Do not allow Rimon to drift on grapes as leaf spotting may occur. REI 12 hr. PHI 14 days. [Group 15] [ovicide]
- spinetoram (Delegate WG) at 4.5 to 7 oz/A in up to 100 gal water per application. Do not exceed four applications per growing season. REI 4 hr. PHI 7 days. [Group 5]
- spinosad (Entrust 80WP) at 2 to 3 oz /A in up to 100 gal water per application. Do not exceed 9 oz /A per season. REI 4 hr. PHI 7 days. [Group 5] OMRI-listed for organic use.
- tebufenozide (Confirm 2F) at 10 to 20 oz/A in up to 100 gal water per application. Do not apply more than 120 oz/A per growing season. REI 4 hr. PHI 14 days. [Group 18A]